Sealing systems for cables and pipes are required in several different applications, for example in ships, offshore industry and buildings, in case of accidents like a fire, an explosion or liquid leaking structures in order to protect important components, areas, lives as well as to delay the spread of fire or leaking water. Sealing systems for cables and pipes are therefore frequently used in several applications in order to protect cable and pipe transits.
Each sealing system comprises a frame secured in a partition wall. The frame material is selected to meet the specific requirement for that particular sealing. The material should be a strong and resistant material, preferably steel or aluminum, and the size of the frame is selected from the number of cables, the dimensions of the cables and the size available in the partition wall.
Each cable in the cable transit is surrounded by an inset block, normally made of two identical sections. Each section is provided with a half cylindrical groove with a diameter that matches the diameter of the cable so that the two sections fit around the cable when put together. The cables and the insert blocks are stored within the frame. A metallic plate provided with protruding flanges that keeps the insert blocks in the right transverse position in the frame is placed between each layer of insert blocks within the frame in order to secure each layer in the frame.
Somewhere within the frame is at least one pressure sealing means placed. The pressure sealing means is, when tensioned, applying a pressure on the inset blocks within the frame so that gaps between the insert blocks and the cables are sealed. The size of the insert blocks are selected to fill the interior width of the frame completely when packed side by side.
One known pressure sealing means comprises two pressure applying wedge-shaped elements placed vertically opposite each other with their thin end facing towards each other, and two tensioning elements that also are wedge-shaped but placed horizontally opposite each other with their thin ends facing towards each other so that flat sides opposite the thin end of the pressure applying elements and the tensioning elements, when placed together, generates a rectangular shaped pressure sealing means.
In order to be able to apply the necessary pressure on the insert blocks within the frame are the tensioning elements connected to each other by at least one treaded screw that extends through the tensioning elements. In one end of the screw is a nut provided so that the two tensioning elements are moved towards each other when the screw is rotated clockwise, and away from each other when it is rotated counter-clockwise. The movement of the two elements towards each other will, as a result of the wedge-shape, force the pressure applying elements away from each other so that the total height of the pressure sealing element is increased. The increased height will consequently apply a pressure on the insert blocks within the frame so that the cable transit is finally sealed. The two pressure applying elements are connected to each other by two small helical springs so that the different elements in the sealing means are held together.
This sealing means however has several drawbacks. One of the drawbacks is that when the final sealing means is inserted in the remaining gap, only slightly larger than the height of the final sealing means, does the pressure applying elements slide sideways in relation to the tensioning elements which, because of the wedge-shaped elements, makes the pressure applying elements turn sideways. This sideways movement, unfortunately, increases the height of the final sealing means and thereby makes it even more difficult to insert it in the gap.
Secondly, if there is a need for modification of the number or types of cables passing through the transit is the final sealing means is the tension applied by the final sealing means released so that the insert blocks could be changed or replaced. The pressure from final sealing means is released by unscrewing the screws and moving the tensioning elements away from each other so that the pressure applying elements are returned to the same position they had before the transit was finally sealed. The two tensioning elements are however not moved similarly when the screws are unscrewed. What happens is that only one of the tensioning elements, normally the one closest to the screw head, moves while the other one remains in the tensioned position within the frame because of friction between the elements in contact with each other. This drawback consequently makes it complicated dismantle the cable transit.
The objective problem for the claimed invention is to provide a pressure sealing means that is easily fitted in and dismantled from the cable transit.
One known solution to overcome the disclosed drawbacks is presented in EP 0 786 061 B1. The pressure sealing means disclosed does however suffer from other drawbacks. One of them is that it is complicated and thereby expensive to manufacture since all wedge-shaped elements and the flexible straps are manufactured in one piece. Another drawback is that if someone of the wedge-shaped elements or the flexible straps is damaged must the entire component be replaced which is costly for the user.
There is consequently still a need for an improved pressure sealing means.